The Effect of Hypertonic Saline Nebulization on Arterial Blood Gas Parameters Among Patients on a Mechanical Ventilator

Introduction Care of the airway is an essential part of the management of patients receiving mechanical ventilation. If the airway is not properly managed, an endotracheal airway can result in retained secretions, airway obstructions, and infections. These complications may prolong mechanical ventilation duration and length of hospital stay and may increase the cost of affordability. Hypertonic saline nebulized suctioning is a technique used to lessen the duration of mechanical air flow and enhance airway clearance, which helps patients on mechanical ventilation breathe easier. Aim The objective of the study is to assess the effectiveness of nebulization with hypertonic saline on arterial blood gas parameters among mechanically ventilated patients. Methods The quasi-experimental design adopted with thirty-five mechanically ventilated samples was chosen using a non-probability purposive sample technique. Following the pre-test in the endotracheal tube, nebulization was given with 2 ml of hypertonic saline over 15-20 mins, two times each day, to the mechanically ventilated patients. Post-test was carried out about 15-20 minutes after the procedure using arterial blood gas analysis results were obtained and interpreted. Results The study reveals that the p values corresponding to the arterial blood gas parameters PCo2, pO2, and HCo3 are less than 0.01 and are significant at a 1% level, and arterial blood gas (ABG) pH is less than 0.05 and is significant at a 5% level; hence there is a high significant difference between the pre-test and post-test mean scores of arterial blood gas parameters PCo2, pO2, HCo3, and ABG pH. Hence, the study concluded that nebulization with hypertonic saline for patients with mechanical ventilators is more effective in improving arterial blood gas parameters.


Introduction
Care of the airway is an essential part of the management of patients receiving mechanical ventilation [1].These complications may prolong mechanical ventilation duration and length of hospital stay and may increase the cost of affordability.Studies have been done over the years to improve airway management strategies [2].Many of the studies emphasize the importance of airway management strategies and their impact on ventilator-associated events [3].Mechanical ventilation is the commonly used intervention in intensive care units, such as airway management for patients [4].
A ventilator is a respiratory device that helps patients when they are unable to breathe by themself.An endotracheal tube is used as a port to connect the patient to the ventilator [5].According to the NCBI Report of 2020, among 165 critically ill patients, 35.7% (59/165) of patients required mechanical ventilators [6].Airway obstruction is common in mechanically ventilated patients due to various problems such as expiratory muscle weakness, mucociliary dysfunction, and unproductive cough.These causes may lead to endotracheal tube blockage that may be firm due to prescribed fluid therapy.The main goal of ICU is to minimize the duration of mechanical ventilation, as prolonged mechanical ventilation was proven to be associated with an increase in mortality and morbidity [7].The goal of ICU is to reduce the duration of mechanical ventilation, as prolonged mechanical ventilation was proven to be associated with an increase in mortality and morbidity [8].
According to a study conducted by Haruna et al., 2022 among 400 samples, re-intubation is required for 51 (12.8%) [9].If the airway is not properly managed, an endotracheal airway can result in retained secretions, airway obstructions, and infections.The most common reason for re-intubation was found to be difficulty in the excretion of secretions.Airway blockage will lead to poor oxygen perfusion in the body.Three essential steps of airway remodeling are humidification, nebulization, and suctioning.Airway clearance techniques will improve mucociliary function and improve the removal of secretions, inflammatory cells, and microorganisms [10].Saline nebulization is a commonly used procedure to loosen the secretions and remove them easily from the endotracheal tube in intensive care units.Hypertonic saline nebulized suctioning has also proven to be effective in clearing airway secretions; however, it is not under regular use [10].Generally, prescribed drugs for nebulization will be used to loosen the secretions [11].Suctioning followed by nebulization with sodium-concentrated saline was demonstrated as an effective treatment to activate the mucociliary function, reduce the thickness of sputum, and reduce the swelling of the airway.It also prevents dryness in the airway.Care of the airway is an essential part of the management of patients receiving mechanical ventilation [12].Airway blockage is directly proportional to gas exchange and acid-base imbalances.The worldwide incidence of people who require intensive care unit admission and mechanical ventilation is up to 20 million annually.Globally, according to Lance et al. (2015), the rate of seriously ill patients increased, and this study showed that around 4312 patients were admitted to three hundred ICUs within thirty-five nations, and among them, nearly 55% of patients were mechanically ventilated patients during intensive care unit admission.
Chakor et al. (2015) found that among the 1150 intensive care admissions, 3.91% of patients required prolonged ventilator support [13].Also among 397 clients, 11.3% needed invasive ventilation.Weaning from mechanical ventilation is an essential element of caring for critically ill patients.So, the main focus of the health care provider is to wean the patient from a mechanical ventilator.Maintaining a patent airway has a major role in weaning the patient from the ventilator.
According to a study conducted by Sudarsanam et al., of the 200 mechanically ventilated patients, at discharge 143 patients (71.5%) had died due to various reasons such as respiratory failure, endotracheal tube obstruction, and so on [14].In the present study, the investigator finds the effect of hypertonic saline nebulization on arterial blood gas parameters among mechanically ventilated patients.

Materials And Methods
The research adopted a quantitative evaluative approach with one group pre-test post-test design.In this study, the independent variable was nebulization with hypertonic saline, and the dependent variable was biophysiological measures and the level of airway clearance.The study was conducted in the ICU complex of Sri Ramaswamy Memorial (SRM) General Hospital, with a sample size of 35.The study included patients who were mechanically ventilated with age above 21 years.Patients who were admitted to the intensive care unit, patients' relatives who signed the informed consent, and patients who were discharged within three days were excluded from this study.Biophysiological measures of pre-and post-test values were collected using arterial blood gas (ABG) parameters (ABG-pH, ABG-pCo2, ABG-po2, ABG-HCo3).The validity obtained from experts in medicine and nursing from SRM General Hospital and Research Institute and SRM College of Nursing provided feedback on the tool's validity.The tool's suitability, relevance, and accuracy were confirmed through validation, and the Institutional Ethical Committee granted formal ethical approval.Data was collected from 35 mechanically ventilated patients chosen using a non-probability purposive sampling technique.Pre-test was done, and as an intervention, endotracheal tube nebulization was given for 15-20 minutes with 2 ml of hypertonic saline two times daily for three days.Followed by endotracheal suctioning performed approximately 5-10 seconds.Post-test was carried out about 15-20 minutes after the procedure by using arterial blood gas analysis.

Results
This study concluded, with a total of 35 mechanical ventilator patients admitted to the ICU.Table 1 reveals that the p-values corresponding to the bio-physiological variables SPO2, PCo2, pO2, and HCo3 are less than 0.01 and are significant at 1% level hence there is a high significant difference between the pretest and posttest mean scores of bio-physiological variables SPO2, PCo2, pO2, and HCo3 also the p-value corresponding to the bio-physiological variable ABG pH is less than 0.05 and is significant at 5% level and hence there is a significant difference between the pretest and post-test mean scores of bio-physiological variable ABG pH.

TABLE 1: Clinical variables
With regard to mechanical ventilation due to CNS disorder 14 (40%), whereas in normal saline group 12 (34.3%)also the reason for mechanical ventilation was CNS disorder.The maximum number of participants in both the hypertonic saline group and the normal saline group received second hourly suctioning, 21 (60%) and 22 (62.9%),respectively.Regarding the duration of mechanical ventilation in the hypertonic saline group majority of participants 19 (54.3%) were on mechanical ventilation for one week also in the normal saline group majority of patients were on mechanical ventilation for one week.Related to the patient's position during suctioning maximum patients both in hypertonic saline group 25 (71.4%) and in normal saline group 26 (74.3%) were in semi-Fowler's position.

CNS -central nervous system
Table 2 explains the p-value corresponding to the bio-physiological variable SPO2 is less than 0.01 and is significant at 1% level hence there is a high significant difference between the post-test level mean scores of bio-physiological variable SPO2.Also, the p+values corresponding to the bio-physiological variables ABG pH, pCo2, pO2, and HCo3 are less than 0.05 and are significant at 5% level, hence, there is a significant difference between the post-test level mean scores of bio-physiological variables ABG pH, pCo2, pO2 and HCo3 of hypertonic saline nebulization.4 shows the distribution of the level of airway clearance of mechanically ventilated patients, and Figure 1 shows results that hypertonic saline was effective in airway clearance at a p-value of 0.000.

Discussion
In the endotracheal tube, nebulization was given with 2 ml of hypertonic saline over 15-20 mins, two times each day for three days.Followed by endotracheal suctioning performed approximately 5-10 seconds for the patients.The patients who were discharged within three days were excluded from this study.The post-test was carried out about 15-20 minutes after the procedure.Biophysiological measurements were obtained from a continuous cardiac monitor, and arterial blood gas analysis reports were obtained.The level of airway clearance was recorded before and after the administration of hypertonic saline nebulized suctioning.Hypertonic saline nebulization is cheap, safe, and effective in maintaining the airway patency of patients who are connected to an artificial airway.The major findings of the study were there is a highly significant difference between the pre-test and post-test mean scores of airway clearance at the p-value >0.001, and is significant at a 1% level.The mean value at the post-test level is less than the mean value at the pre-test level, and the study concludes that hypertonic saline is effective in airway clearance.The p-values corresponding to the biophysiological variables SPO2, PCo2, pO2, and HCo3 are less than 0.01 and are significant at a 1% level; hence, there is a high significant difference between the pre-test and post-test mean scores of bio-physiological variables SPO2, PCo2, pO2, and HCo3 of hypertonic saline nebulization.

Conclusions
The study concludes that the effectiveness of nebulization with hypertonic saline on biophysiological measures and the level of airway clearance among mechanically ventilated patients.The study also concludes that the nebulization with hypertonic saline for patients with mechanical ventilators is more effective in maintaining arterial blood gas parameter values like SPO2 and pO2, reducing pCO2, and maintaining pH at normal range, and also more effective on airway clearance.The nurse has the primary role in maintaining a patent airway for mechanically ventilated patients.So, it is important to improve their knowledge and practice related to airway clearance.This can be enabled by applying the research into the practice.

FIGURE 1 :
FIGURE 1: Results showing that hypertonic saline was effective in airway clearance at a p-value of 0.000 Percentage distribution of the level of airway clearance of mechanically ventilated patients among the hypertonic saline group